Controlling method for thermoelectric cooling device and heat-dissipating module employing same

ABSTRACT

A controlling method for a thermoelectric cooling device is provided. The thermoelectric cooling device has a cold side and a hot side. After the thermoelectric cooling device is enabled, a temperature of the cold side and an ambient temperature around the thermoelectric cooling device are acquired. By judging whether the ambient temperature is higher than or equal to a preset reference temperature, an initial value of a duty cycle corresponding to an electric energy to be received by the thermoelectric cooling device is set. Then, a judging step is performed to judge whether the temperature of the cold side is higher than or equal to the ambient temperature. If the judging condition is satisfied, the duty cycle is increased by a specified percentage. If the judging condition is not satisfied and the duty cycle is higher than 0%, the duty cycle is decreased by the specified percentage.

FIELD OF THE INVENTION

The present invention relates to a controlling method, and moreparticularly to a controlling method for a thermoelectric cooling deviceand a heat-dissipating module employing the same.

BACKGROUND OF THE INVENTION

Recently, with increasing development of industrial technologies andscience, a variety of electronic devices are gradually improved, so thatthe functions and the processing speeds of these electronic devices areenhanced. Consequently, the electronic components within theseelectronic devices must have high power or high integration level.During operation of the electronic devices, the electronic componentsmay generate energy in the form of heat. If no proper heat-dissipatingmechanism is provided to transfer enough heat to the ambient air, theelevated operating temperature may result in damage of the electroniccomponents or breakdown of the whole electronic device. For maintainingnormal operations of the electronic device and extending the use life ofthe electronic device, it is important to dissipate the heat from theelectronic device.

Generally, the heat-dissipating mechanism for removing heat from theoptical components or electronic components of a high power electronicdevice (e.g. a projector or a personal computer) includes a heatsinkwith a plurality of heat pipes or a liquid cooling mechanism. However,the applications of the heatsink and the liquid cooling mechanism arerestricted. As known, the heat of the components that generate highpower and withstand low temperature can't be effectively removed by theheatsink or the liquid cooling mechanism. For increasingheat-dissipating efficiency and reliability, a thermoelectric coolingdevice is gradually used.

The thermoelectric cooling device is substantially a PN semiconductordevice. When a current passes through the thermoelectric cooling device,two sides of the thermoelectric cooling device become a cold side and ahot side, respectively. Due to a temperature difference between the coldside and hot side, the temperature of the cold side is very low. Thecold side of the thermoelectric cooling device is in contact with thecomponent to be cooled. The hot side of the thermoelectric coolingdevice is hotter than the cold side. However, the use of thethermoelectric cooling device still has some drawbacks. For example, ifthe temperature of the cold side of the thermoelectric cooling device islower than the ambient temperature, the thermoelectric cooling deviceand the inner component of the electronic device may result in dew oreven generate moisture vapor. Under this circumstance, the reliabilityand the use life of the electronic device are reduced.

Therefore, there is a need of providing a controlling method for athermoelectric cooling device and a heat-dissipating module using thethermoelectric cooling device in order to eliminate the above drawbacks.

SUMMARY OF THE INVENTION

The present invention provides a controlling method for a thermoelectriccooling device and a heat-dissipating module using the thermoelectriccooling device. By judging the relationship between the temperature ofthe cold side of the thermoelectric cooling device and the ambienttemperature, the duty cycle corresponding to the electric energy to bereceived by the thermoelectric cooling device is selectively increasedor decreased. In case that the temperature of the cold side of thethermoelectric cooling device is higher than or equal to the ambienttemperature, the chilling efficiency of the cold side of thethermoelectric cooling device is enhanced by increasing the duty cycle.In case that the temperature of the cold side of the thermoelectriccooling device is lower than the ambient temperature, the duty cycle isdecreased, so that the possibility of resulting in dew and generatingmoisture vapor is minimized. When the heat-dissipating module of thepresent invention is used to remove heat from electronic components ofan electronic device, the influence of the moisture vapor on theelectronic components are largely reduced. Consequently, the reliabilityand the use life of the electronic device are enhanced.

In accordance with an aspect of the present invention, there is provideda controlling method for a thermoelectric cooling device. Thethermoelectric cooling device has a cold side and a hot side. In a step(a), the thermoelectric cooling device is enabled, and a temperature ofthe cold side and an ambient temperature around the thermoelectriccooling device are acquired. Then, a step (b) is performed to judgewhether the ambient temperature is higher than or equal to a presetreference temperature. In a step (c), an initial value of a duty cyclecorresponding to an electric energy to be received by the thermoelectriccooling device is set according to a judging result of the step (b).Then, a step (d) is performed to judge whether the temperature of thecold side is higher than or equal to the ambient temperature. In a step(e), if the judging condition of the step (d) is satisfied, the dutycycle is increased by a specified percentage, and the step (d) isrepeatedly performed. In a step (f), if the judging condition of thestep (d) is not satisfied, the duty cycle is decreased by the specifiedpercentage and the step (d) is repeatedly performed by judging whetherthe duty cycle is higher than 0%.

In accordance with another aspect of the present invention, there isprovided a heat-dissipating module. The heat-dissipating modulecomprises a thermoelectric cooling device, a power supply circuit, afirst temperature sensor, a second temperature sensor, and a controller.The thermoelectric cooling device has a cold side and a hot side. Thepower supply circuit is electrically connected with the thermoelectriccooling device and operated at a duty cycle for providing electricenergy to the thermoelectric cooling device and driving thethermoelectric cooling device. The first temperature sensor is disposedadjacent to the cold side of the thermoelectric cooling device fordetecting the temperature of the cold side. The second temperaturesensor is used for detecting the ambient temperature around thethermoelectric cooling device. The controller is electrically connectedwith the first temperature sensor, the second temperature sensor and thepower supply circuit, judges whether the temperature of the cold side ofthe thermoelectric cooling device is higher than or equal to the ambienttemperature according to a detecting result of the first temperaturesensor and the second temperature sensor, and adjusts the duty cycle ofthe power supply circuit according to a judging result for adjusting theelectric energy provided by the power supply circuit correspondingly.

The above contents of the present invention will become more readilyapparent to those ordinarily skilled in the art after reviewing thefollowing detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic circuit block diagram illustrating thearchitecture of a heat-dissipating module according to an embodiment ofthe present invention;

FIG. 2 is a schematic view illustrates some components of theheat-dissipating module according to the embodiment of the presentinvention;

FIG. 3 is a flowchart illustrating a method for controlling athermoelectric cooling device according to an embodiment of the presentinvention; and

FIG. 4 is a flowchart illustrating a method for controlling athermoelectric cooling device according to another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing descriptions of preferred embodiments of this invention arepresented herein for purpose of illustration and description only. It isnot intended to be exhaustive or to be limited to the precise formdisclosed.

FIG. 1 is a schematic circuit block diagram illustrating thearchitecture of a heat-dissipating module according to an embodiment ofthe present invention. As shown in FIG. 1, the heat-dissipating module 1comprises a first temperature sensor 10, a second temperature sensor 11,a power supply circuit 12, a controller 13, and a thermoelectric coolingdevice 14. The power supply circuit 12 is electrically connected withthe thermoelectric cooling device 14. Moreover, the power supply circuit12 is operated at a specified duty cycle in order to provide electricenergy to the thermoelectric cooling device 14 and drive thethermoelectric cooling device 14. The thermoelectric cooling device 14is a PN semiconductor device with a cold side 140 and a hot side 141(see FIG. 2). The cold side 140 and the hot side 141 are located at twoopposite sides of the thermoelectric cooling device 14. After thethermoelectric cooling device 14 is enabled by receiving the electricenergy from the power supply circuit 12, the cold side 140 of thethermoelectric cooling device 14 generates a chilling effect. Meanwhile,the hot side 141 is relatively hotter than the cold side 140. The firsttemperature sensor 10 is used for detecting the temperature of the coldside 140 of the thermoelectric cooling device 14. The second temperaturesensor 11 is used for detecting an ambient temperature around thethermoelectric cooling device 14, i.e. the ambient temperature aroundthe heat-dissipating module 1.

The controller 13 is electrically connected with the first temperaturesensor 10, the second temperature sensor 11 and the power supply circuit12. According to the detecting results of the first temperature sensor10 and the second temperature sensor 11, the controller 13 judgeswhether the temperature of the cold side 140 of the thermoelectriccooling device 14 is higher than or equal to the ambient temperature.According to the judging result, a duty cycle of the power supplycircuit 12 is adjusted by the controller 13. After the duty cycle of thepower supply circuit 12 is adjusted, the electric energy provided by thepower supply circuit 12 is correspondingly adjusted.

FIG. 2 is a schematic view illustrates some components of theheat-dissipating module according to the embodiment of the presentinvention. As shown in FIGS. 1 and 2, the cold side 140 of thethermoelectric cooling device 14 is located near an electronic component9. After the thermoelectric cooling device 14 is enabled, the cold side140 of the thermoelectric cooling device 14 can cool the electroniccomponent 9. In addition, the first temperature sensor 10 is disposedadjacent to the cold side 140 of the thermoelectric cooling device 14.Of course, the first temperature sensor 10 may be in direct contact withthe cold side 140 of the thermoelectric cooling device 14 in order tomeasure the temperature of the cold side 140 more accurately.

Optionally, the heat-dissipating module 1 further comprises a pluralityof fins 15. As shown in FIG. 2, the fins 15 are disposed on the hot side141 of the thermoelectric cooling device 14 for transferring the heat ofthe hot side 141 through thermal conduction. Optionally, theheat-dissipating module 1 further comprises a third temperature sensor16. The third temperature sensor 16 is located near or disposed on thehot side 141 of the thermoelectric cooling device 14. Moreover, thethird temperature sensor 16 is electrically connected with thecontroller 13. The temperature sensor 16 is used for detecting thetemperature of the hot side 141 of the thermoelectric cooling device 14.In case that the temperature of the hot side 141 of the thermoelectriccooling device 14 exceeds a protective temperature, the controller 13may control the power supply circuit 12 to stop providing electricenergy to the thermoelectric cooling device 14. Consequently, theheat-dissipating module 1 can be protected. The protective temperaturemay be previously determined according to the practical requirements.For example, the maximum withstandable temperature may be set as theprotective temperature.

Hereinafter, a method for controlling the thermoelectric cooling device14 by the controller 13 will be illustrated with reference to FIGS. 1, 2and 3. FIG. 3 is a flowchart illustrating a method for controlling athermoelectric cooling device according to an embodiment of the presentinvention. Firstly, in the step S1, the heat-dissipating module 1 isenabled (i.e. the thermoelectric cooling device 14 is enabled). Then, inthe step S2, the temperature of the cold side 140 of the thermoelectriccooling device 14 and the ambient temperature around the thermoelectriccooling device 14 are acquired. The temperature of the cold side 140 ofthe thermoelectric cooling device 14 is detected by the firsttemperature sensor 10. The ambient temperature around the thermoelectriccooling device 14 is detected by the second temperature sensor 11. Then,in the step S3, the controller 13 judges whether the ambient temperatureis higher than or equal to a preset reference temperature. For example,the preset reference temperature is 30° C., but is not limited thereto.

Then, in the step S4, an initial value of a duty cycle of the powersupply circuit 12 corresponding to the electric energy to be received bythe thermoelectric cooling device 14 is set according to the judgingresult of the step S3. The step S4 comprises two sub-steps S40 and S41.In particular, either the sub-step S40 or the sub-step S41 is performedaccording to the judging result of the step S3. If the ambienttemperature is higher than or equal to the preset reference temperature(e.g. 30° C.), the initial value of the duty cycle of the power supplycircuit 12 is set as 50% by the controller 13. That is, the sub-step S40is performed. Under this circumstance, since the power supply circuit 12can provide higher electric energy to the thermoelectric cooling device14 at the initial stage, the cooling rate of the cold side 140 of thethermoelectric cooling device 14 is higher. Meanwhile, in response tothe high ambient temperature, the heat of the electronic component 9 canbe quickly removed at the higher cooling rate by the thermoelectriccooling device 14.

On the other hand, if the ambient temperature is lower than the presetreference temperature, the judging condition of the step S3 is notsatisfied. Meanwhile, the initial value of the duty cycle of the powersupply circuit 12 is set as 0% by the controller 13. That is, thesub-step S41 is performed. Under this circumstance, since the ambienttemperature is low, the power supply circuit 12 needn't to provide highelectric energy to the thermoelectric cooling device 14 immediately andthe cooling rate of the cold side 140 of the thermoelectric coolingdevice 14 is lower at the initial stage. Therefore, the initial value ofthe duty cycle of the power supply circuit 12 is set as 0% by thecontroller 13.

After the step S4, the step S5 is performed. In the step S5, thecontroller 13 judges whether the temperature of the cold side 140 of thethermoelectric cooling device 14 is higher than or equal to the ambienttemperature. If the judging condition of the step S5 is satisfied, thecold side 140 of the thermoelectric cooling device 14 will not result indew. Consequently, the duty cycle of the power supply circuit 12 iscontinuously increased to increase the output electric energy of thepower supply circuit 12. Under this circumstance, the step S6 isperformed. In the step S6, the duty cycle of the power supply circuit 12is increased by a specified percentage (e.g. 1%) by the controller 13.Meanwhile, the temperature of the cold side 140 is continuouslydecreased, and the chilling effect is enhanced. Consequently, the heatof the electronic component 9 can be quickly removed at the highercooling rate by the thermoelectric cooling device 14.

On the other hand, if the judging condition of the step S5 is notsatisfied, the cold side 140 of the thermoelectric cooling device 14 mayresult in dew and generate moisture vapor. For minimizing thepossibility of resulting in dew and generating moisture vapor, the dutycycle of the power supply circuit 12 should be decreased. Then, the stepS7 is performed to judge whether the duty cycle of the power supplycircuit 12 is higher than 0%. If the judging condition of the step S7 isnot satisfied (Namely, if the duty cycle of the power supply circuit 12is equal to 0%), the step S5 is performed again. Whereas, if the judgingcondition of the step S7 is satisfied, the step S8 is performed. In thestep S8, the duty cycle of the power supply circuit 12 is decreased by aspecified percentage (e.g. 1%) by the controller 13. Since the dutycycle of the power supply circuit 12 is decreased, the output electricenergy of the power supply circuit 12 is decreased. Under thiscircumstance, the temperature of the cold side 140 of the thermoelectriccooling device 14 is gradually increased, and the possibility ofresulting in dew and generating moisture vapor is minimized.

FIG. 4 is a flowchart illustrating a method for controlling athermoelectric cooling device according to another embodiment of thepresent invention. In this embodiment, the sub-step S40 of the step S4of FIG. 3 is replaced by the sub-step S40′. In the step S40′, an initialvalue of a duty cycle of the power supply circuit 12 corresponding tothe electric energy to be received by the thermoelectric cooling device14 is set according to the judging result of the step S3 after adelaying time. Under this circumstance, the cooling rate of the coldside 140 of the thermoelectric cooling device 14 is gradually increased,and the heat of the electronic component 9 is gradually removed by thethermoelectric cooling device 14. Consequently, the possibility ofresulting in dew and generating moisture vapor is minimized.

From the above descriptions, the present invention provides acontrolling method for a thermoelectric cooling device and aheat-dissipating module using the thermoelectric cooling device. Byjudging the relationship between the temperature of the cold side of thethermoelectric cooling device and the ambient temperature, the dutycycle corresponding to the electric energy to be received by thethermoelectric cooling device is selectively increased or decreased. Incase that the temperature of the cold side of the thermoelectric coolingdevice is higher than or equal to the ambient temperature, the chillingefficiency of the cold side of the thermoelectric cooling device isenhanced by increasing the duty cycle. In case that the temperature ofthe cold side of the thermoelectric cooling device is lower than theambient temperature, the duty cycle is decreased, so that thepossibility of resulting in dew and generating moisture vapor isminimized. When the heat-dissipating module of the present invention isused to remove heat from electronic components of an electronic device,the influence of the moisture vapor on the electronic components arelargely reduced. Consequently, the reliability and the use life of theelectronic device are enhanced.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiment. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A controlling method for a thermoelectric coolingdevice, the thermoelectric cooling device having a cold side and a hotside, the method comprising steps of: (a) enabling the thermoelectriccooling device, and acquiring a temperature of the cold side and anambient temperature around the thermoelectric cooling device; (b)judging whether the ambient temperature is higher than or equal to apreset reference temperature; (c) setting an initial value of a dutycycle corresponding to an electric energy to be received by thethermoelectric cooling device according to a judging result of the step(b); (d) judging whether the temperature of the cold side is higher thanor equal to the ambient temperature; (e) if the judging condition of thestep (d) is satisfied, increasing the duty cycle by a specifiedpercentage, and repeatedly performing the step (d); and (f) if thejudging condition of the step (d) is not satisfied, decreasing the dutycycle by the specified percentage and repeatedly performing the step (d)by judging whether the duty cycle is higher than 0%.
 2. The controllingmethod according to claim 1, wherein in the step (c), if the ambienttemperature is higher than or equal to the preset reference temperature,the initial value of the duty cycle is set as 50%.
 3. The controllingmethod according to claim 1, wherein in the step (c), if the ambienttemperature is higher than or equal to the preset reference temperature,the initial value of the duty cycle is set as 50% after a delaying time.4. The controlling method according to claim 1, wherein in the step (c),if the ambient temperature is lower than the preset referencetemperature, the initial value of the duty cycle is set as 0%.
 5. Thecontrolling method according to claim 1, wherein in the step (b), thepreset reference temperature is 30° C.
 6. The controlling methodaccording to claim 1, wherein in the step (f), if the duty cycle ishigher than 0%, the duty cycle is decreased by the specified percentage,and the step (d) is repeatedly done.
 7. The controlling method accordingto claim 1, wherein in the step (f), if the duty cycle is equal to 0%,the step (d) is repeatedly done.
 8. A heat-dissipating module,comprising: a thermoelectric cooling device having a cold side and a hotside; a power supply circuit electrically connected with thethermoelectric cooling device and operated at a duty cycle for providingelectric energy to the thermoelectric cooling device and driving thethermoelectric cooling device; a first temperature sensor disposedadjacent to the cold side of the thermoelectric cooling device fordetecting a temperature of the cold side; a second temperature sensorfor detecting an ambient temperature around the thermoelectric coolingdevice; and a controller electrically connected with the firsttemperature sensor, the second temperature sensor and the power supplycircuit, judging whether the temperature of the cold side of thethermoelectric cooling device is higher than or equal to the ambienttemperature according to a detecting result of the first temperaturesensor and the second temperature sensor, and adjusting the duty cycleof the power supply circuit according to a judging result for adjustingthe electric energy provided by the power supply circuitcorrespondingly.
 9. The heat-dissipating module according to claim 8,wherein the controller performs a controlling method comprising stepsof: (a) enabling the thermoelectric cooling device, and acquiring thetemperature of the cold side and the ambient temperature around thethermoelectric cooling device; (b) judging whether the ambienttemperature is higher than or equal to a preset reference temperature;(c) setting an initial value of the duty cycle corresponding to anelectric energy to be received by the thermoelectric cooling deviceaccording to a judging result of the step (b); (d) judging whether thetemperature of the cold side is higher than or equal to the ambienttemperature; (e) if the judging condition of the step (d) is satisfied,increasing the duty cycle by a specified percentage, and repeatedlyperforming the step (d); and (f) if the judging condition of the step(d) is not satisfied, decreasing the duty cycle by the specifiedpercentage and repeatedly performing the step (d) by judging whether theduty cycle is higher than 0%.
 10. The heat-dissipating module accordingto claim 8, wherein the first temperature sensor is in direct contactwith the cold side of the thermoelectric cooling device.
 11. Theheat-dissipating module according to claim 8, further comprising aplurality of fins disposed on the hot side of the thermoelectric coolingdevice for transferring the heat of the hot side.
 12. Theheat-dissipating module according to claim 8, further comprising a thirdtemperature sensor located near the hot side of the thermoelectriccooling device and electrically connected with the controller fordetecting the temperature of the hot side, wherein when the temperatureof the hot side of the thermoelectric cooling device exceeds aprotective temperature, the controller controls the power supply circuitto stop providing electric energy to the thermoelectric cooling device.